Excitation-free cage type tapping switch for transformer

Abstract

The invention relates to an excitation-free cage type tapping switch for a transformer, comprising an upper support seat and a lower support seat. Insulated rods are circumferentially connected between the upper support seat and the lower support seat; annular fixed contacts are arranged at intervals along the axial direction of the insulated rods; moving contact components are arranged between the upper support seat and the lower support seat as well as inside the annular fixed contacts; the moving contact components are connected with an upper driving device and a lower driving device; and moving contacts spanned with two fixed contacts adjacent to the moving contact are arranged on the peripheries of the moving contact components corresponding to the annular fixed contacts. The excitation-free cage type tapping switch is characterized in that the annular fixed contacts are connected with the peripherally-arranged insulated rods in a staggered mode, two up-down adjacent annular fixedcontacts are not connected with the same insulated rod; and an oil gap is reserved between the annular fixed contact and the insulated rod which is not adjacent to the annular fixed contact. Under the condition of the same axial interval of the annular fixed contacts, the insulated creepage distance can be doubly increased and the insulating level inside the switch can be improved or the axial height of the switch can be effectively reduced. The excitation-free cage type tapping switch has the characteristics of compact structure and reasonable design.

Description

technical field [0001] The invention relates to an off-excitation tap changer for a transformer, which is a further improvement on the existing off-excitation cage tap changer. Background technique [0002] In the Chinese patent CN200944364, a non-excitation cage tap changer is disclosed. Its structure is to set annular static contacts, which are distributed along the axial direction and fixed on the insulating rods arranged in the circumferential direction through the outer circle, so that The ring static contact can enhance the mechanical strength and rigidity of the cage insulator. The switch movable contact slides up and down in the ring of the ring-shaped static contact and bridges two adjacent static contacts to realize the function of voltage regulation. The switch has many contact points and can realize large current, and has good rigidity. In view of the above characteristics, the switch is often used in high-voltage occasions. The higher the voltage of the adjace...

AI Technical Summary

Problems solved by technology

In view of the above characteristics, the switch is often used in high-voltage occasions. The higher the voltage of the adjacent static contacts, the greater the creepage margin between adjacent static contacts according to the insulation properties of the insulating rod materials arranged in the circumferential direction. , so when the voltage between the contacts is high and there are many gears, the height of the switch will be very high, which not only makes the overall rigidity of the switch worse, but also takes up a lot of space due to its large size, which is not convenient for its installation on the transformer

At present, the capacity of a single transformer is getting bigger and bigger, and the voltage level is getting higher and higher, and the above defects are also more prominent.

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